1. Field of the Invention
This invention relates to sets of prepaints methods of formulating paint lines using its sets of prepaints, useful paints, including as architectural coatings, industrial coatings, graphic art coatings, elastomeric coatings and non-cementitious, aggregate finish coatings, from sets of prepaint compositions.
2. Description of Related Art
For decades, professional painters/contractors and do-it-yourself consumers have been able to purchase paints that are tinted at the point-of-sale rather than at the manufacturing facility. This postponement of product differentiation permits the buyer to specify the desired color of the paint from a wide variety of choices rather than a limited number of colors once produced by the paint manufacturer.
While not practiced commercially, it is also theoretically known in the paint industry to postpone product differentiation of the paint components themselves as long as possible in the paint manufacturing process. See, for example, Carola Grundfelt-Forsius"" paper in Faerg Lack Scand 43(2), pages 5-6 (1997) which describes the use of intermediaries or components, i. e., mixtures of several of the paint raw material ingredients, that are mixed together with the tinting pastes to yield different types of paints. Grundfelt-Forsius provides an example of such a system employing a polyurethane binder for a solution polymer system.
The methods of postponement of product differentiation offers the buyer the flexibility of selecting the desired final paints, whether it be the color of the paint or the type of paint while at the same time permitting the paint manufacturer or seller (retail or wholesale or distributor) to minimize inventories of raw materials, intermediates and final products as well as stock outages.
Despite these benefits, paint manufacturers have only been able to successfully employ the postponement in product differentiation to paint systems based on solution polymers. Paint manufacturers have not been successful in postponing product differentiation of paint components in latex polymer-based paint systems. Since the majority of paints used today are based on latex polymers, there is a need for a practical method for postponing product differentiation in a latex polymer-based paint system.
It is considerably more difficult to formulate a stable paint when using latex emulsion polymers rather than solution polymers because of latex instability. Emulsion polymers are very sensitive to the solvents and surface active agents commonly found in paint formulations, such as surfactants, dispersants, rheology modifiers, and co-solvents. Solution polymers are by definition soluble in the solvent they are supplied in, and there is no thermodynamic driving force causing the polymer molecules to agglomerate or become unstable. In contrast, latex polymers contain the polymeric material in particles that are insoluble in water. These particles require considerable surface modifications to render them stable when supplied in an aqueous medium. If the surface modification is inadequate, the latex particles attach to one another forming a coagulated mass which then separates out of the latex paint. Paint formulating with a latex system is very difficult because the surface active materials in the formulation disrupt the delicate balance of surface forces that stabilize the latex particles in a water medium.
The difference between latex polymer systems (also referred to herein as xe2x80x9cemulsionxe2x80x9d) and solution polymer systems is further explained in Temple C. Patton""s book entitled Paint Flow and Pigment Dispersion (New York: John Wiley and Sons, Inc., 1979, pages 192-193). Here the author describes the drying processes for the two systems. The main difference lies in the time required for each polymer to reach an irreversible state. Latex polymers reach this state much faster than solution polymers and thus make paints based on latex polymers more difficult to stabilize than paints based on solution polymers. In discussing xe2x80x9csolvent-type coatingsxe2x80x9d, (which contain solution polymers) the author writes xe2x80x9c . . . the liquid vehicle flows rather than deforms around the pigment particles on drying. This flow assists the compaction process as the film shrinks because of loss of volatile solvent. Although the vehicle becomes more viscous as solvent evaporates, flow persists through most of the drying cycle.xe2x80x9d As the author paints out, the solution polymer is able to flow though most of the drying cycle as the solvent evaporates. This is not time for polymer emulsion. The same author notes: xe2x80x9c . . . there is a preliminary flow of the latex suspension. This takes place before the time when the latex particles are first forced to come into intimate contact because of initial water loss. However, after this relatively short but very important initial flow, pigment compaction to achieve a high critical pigment volume concentration (CPVC) is achieved mainly by plastic deformation and coalescence of the latex particles.xe2x80x9d Coalescence is the irreversible contact between latex particles. Such irreversible contact can occur in a liquid paint based on latex polymers, but not in a liquid paint based on solution polymers. Thus, paints based on latex polymers are more difficult to formulate.
There is a great need to develop a set of prepaints and a method of formulating paints based on latex polymers using sets of prepaints.
Paint formulating involves the process of selecting and admixing appropriate paint ingredients in the correct proportions to provide a paint with specific processing and handling properties, as well as a final dry paint film with the desired properties. The major ingredients of latex paint formulations are a binder, an opacifying pigment, optional pigment extenders, and water. Common optional additives include defoamers, coalescents, plasticizers, thickeners, non-thickening rheology modifiers, opacifying agents, driers, anti-skinning agents, surfactants, mildewcides, biocides and dispersants. After the latex paint is formulated and applied to a surface, the paint dries by evaporation of the water, with or without the application of heat, and the binder forms a film containing therein the pigment and the pigment extender particles, if any.
Formulating paints is complexxe2x80x94it is not simply a matter of mixing a few paint ingredients in different ratios. Rather, it involves the selection and mixing of different paint ingredients in different ratios depending on the type of paint desired. This requires paint manufacturers to store many different paint ingredients and change paint ingredients during manufacture depending on the specific paint type being prepared.
Furthermore, it requires those in the supply chain, especially the paint retailers, to carry a large inventory of paints in the warehouse and on the store shelves in order to offer a range of paints, such as various sheen levels, tint bases, paints for exterior use, paints for interior use, and paints of varying quality. It would be desirable to make paints, either at a relatively large-scale industrial plant or at a relatively smaller-scale, point-of-sale or point-of-use location using a limited number of paint ingredients to prepare all of these different paint formulations, thus, minimizing the number and type of paint ingredients needed to make a range of paints.
A xe2x80x9cpaint linexe2x80x9d, as used herein, includes at least two different paints which offer dried film properties which differ materially from each other in at least one observable property such as sheen, outdoor durability or color depth. A paint line may include, for example, three paints the dried films of which have different sheen levels, two paints the dried films of which have suitable interior or exterior performance, or four paints the dried films of which offer different quality or performance levels such as may be evidenced, for example, by different levels of scrub resistance.
A paint line could, more particularly, include four different paints, the dried films of which have different sheen levels, typically marketed as gloss; semi-gloss; eggshell, satin, or low lustre; and flat. The sheen is determined by the volume and type of the binder(s), pigment(s), and extender(s), if any, in the paint.
In addition to the various sheen levels, paints are commonly formulated to be neutral or accent (no or very low level of opacifying pigment), untinted (white) or tinted to a wide variety of colors using different tint bases, including pastel or light tones, medium or mid-tones, and deep tones. This capability requires a paint line having as many as five paints. Also, paints are formulated for exterior or interior use. And, paints are formulated to provide certain levels of performance properties, such as may be marketed as good/standard, better and best/premium.
Paint manufacturers and retailers typically offer a range of paints which including at least two paint lines. By xe2x80x9cthe range including at least two paint linesxe2x80x9d herein is meant that the discrete elected levels of the observable property defining a first paint line are combined with the discrete elected levels of the observable property defining a second paint line, etc. to define the paints in the range of paints.
To prepare a range of paints which includes four paint lines may require preparing paints encompassing four sheen levels, four tint bases, interior and exterior use, and three quality levels. For all combinations 96 different paint formulations (4xc3x974xc3x972xc3x973) may be needed. Also encompassed, however, is a range of paints in which certain of the defined paints, certain proportion, including up to as high as 10-60%, of the total number of paints, are selected to be omitted, for example, for commercial reasons or because they are not stable as defined herein. Further contemplated is a range of paints in which the observable properties of the dried paint films substantially, but not exactly, fulfill the standard definitions for example, the sheen of a dried outdoor mid-tone gloss paint in the standard, better, and premium lines may differ by a few points without departing from the meaning of a range of paints of this invention.
As used herein, xe2x80x9cpaintxe2x80x9d is term used in its broadest sense and includes any coating that may be applied to a surface for decorative, protective or both purposes. Specifically included are those systems employed for architectural coatings, industrial coatings, elastomeric coatings and non-cementitious, aggregate finish coatings employed as the topcoat over walls and in an exterior insulation and finishing system (referred to hereinafter as xe2x80x9cEIFSxe2x80x9d).
As used herein, prepaints are xe2x80x9cmutually compatiblexe2x80x9d if the paints formed by admixing the prepaints do not evidence signs of colloidal instability such as flocculation. Preferably, the paints formed from the prepaints exhibit less than 5 g of residue such as gel and grit per liter of paint when the paint is passed through a 325 mesh screen. More preferably, the paints formed from the prepaints exhibit less than 1 g of residue per liter of paint when the paint is passed through a 325 mesh screen. If the additives included to enhance specific paint properties, and colorants are fully compatible, i.e., they can be blended at any ratio without inducing colloidal instability, then they can be blended in any combination falling within the formulation space needed to achieve the desired property profile in the final paint. It is sufficient, however, for the prepaints, optional additives included to enhance specific paint properties, and colorants to be compatible, i. e., they can be blended at desired ratios without inducing colloidal instability to achieve the desired property profile in the range of paints.
In order to minimize the number of paint ingredients needed to prepare a range of paints one needs to consider the extremes of key properties required by the range of paints and formulate prepaints which are capable of being blended in various combinations to provide the key properties required, at their extreme values and at intermediate points as well. Specific properties may be improved by adding paint additives which enhance the desired property.
The above goal is achieved by employing a set of different, but mutually compatible, fluid prepaints sufficient to formulate at least one paint line. The set comprises (i) at least one opacifying prepaint comprising at least one opacifying pigment; (ii) at least one extender prepaint comprising at least one extender pigment; and (iii) at least one binder prepaint comprising at least one latex polymeric binder;
Preferably, the number of prepaints is 3-15.
Also provided is a method of forming at least one paint line comprises the steps of:
(a) providing a set of different, but mutually compatible, fluid prepaints sufficient to formulate at least one paint line, which set comprises: (i) at least one opacifying prepaint including at least one opacifying pigment; (ii) at least one extender prepaint including at least one extender pigment; and (iii) at least one binder prepaint including at least one latex polymeric binder; and
(b) dispensing a predetermined amount each of the prepaints into containers or applicator(s) to form the paint line.
Preferably, the total number of prepaints is 3-15.
The method may further include the step of mixing the prepaints before, while, or after they are dispensed into the containers or before or while they are dispensed into the applicator(s).
Further provided is a method of forming a range of paints. The range includes at least two paint lines. The methods comprises the steps of:
(a) providing a set of different, but mutually compatible, fluid prepaints sufficient to formulate the range of paints, which set comprises (i) at least one opacifying prepaint including at least one opacifying pigment; (ii) at least one extender prepaint including at least one extender pigment; (iii) at least one binder prepaint including at least one latex polymeric binder; and (iv) at least one additional different prepaint selected from the group consisting of prepaints (i), (ii), and (iii); and
(b) dispensing a predetermined amount of each of the prepaints into containers or applicator(s) to form the paint lines.
Preferably, the total number of prepaints is 4-15.
The methods may further comprise the step of mixing the prepaints before, while, or after they are dispensed into the container or before or while they are dispensed into the applicator(s). The methods may further include the step of adjusting the viscosity of the dispensed prepaints before, while, or after they are dispensed into the container or before or while they are dispensed into the applicator(s) using a thickener, water, or a mixture thereof. The methods may further comprise the step of adding additional materials that enhance the application or final performance properties of the paint, including aggregates and thickeners. The methods may further include the step of adding at least one colorant to the dispensed prepaints. The methods may be carried out at a paint manufacturing facility, a point-of-sale, or a point-of-use and may be controlled by a computer.
In another embodiment, a set of different, but mutually compatible fluid prepaints sufficient to form at least one paint line useful as an elastomeric coating is provided. The set comprises (i) at least one opacifying prepaint comprising at least one opacifying pigment; (ii) at least one extender prepaint comprising at least one extender pigment; and (iii) at least one binder prepaint comprising at least one latex polymer binder having a Tg less than about 0xc2x0 C.
Further provided is a method of forming at least one paint line useful as an elastomeric coating. The method comprises the steps of:
(a) providing a set of different, but mutually compatible, fluid prepaints, which set comprises (i) at least one opacifying prepaint comprising at least one opacifying pigment; (ii) at least one extender prepaint comprising at least one extender pigment; and (iii) at least one binder prepaint comprising at least one latex polymeric binder having a Tg less than about 0xc2x0 C.; and
(b) dispensing a predetermined amount of each of the prepaints into containers or applicator(s) to form the paint line.
Further provided is a method of forming a range of paints. The range comprises at least two paint lines useful as elastomeric coatings. The method comprises the steps of:
(a) providing a set of different, but mutually compatible, fluid prepaints sufficient to formulate at least two paint lines, which set comprises: (i) at least one opacifying prepaint comprising at least one opacifying pigment; (ii) at least one extender prepaint comprising at least one extender pigment; (iii) at least one binder prepaint comprising at least one latex polymer binder having a Tg less than about 0xc2x0 C.; and (iv) at least one additional different fluid prepaint selected from the group consisting of prepaints (i), (ii), and (iii); and
(b) dispensing a predetermined amount of each of the prepaints into containers or applicator(s) devices to form the paint lines. In another embodiment, a set of different, but mutually compatible, fluid non-cementitious prepaints sufficient to form at least one paint line useful as a non-cementitious, aggregate finish is provided. The set comprises (i) at least one opacifying prepaint comprising at least one opacifying pigment; (ii) at least one extender prepaint comprising at least one extender pigment; (iii) at least one binder prepaint comprising at least one latex polymeric binder; and (iv) at least one prepaint comprising aggregate.
Also provided is a method of forming at least one paint line useful as a non-cementitious, aggregate finish. The method comprises the steps of:
(a) providing a set of different, but mutually compatible, fluid non-cementitious prepaints, which set comprises: (i) at least one opacifying prepaint comprising at least one opacifying pigment; (ii) at least one extender prepaint comprising at least one extender pigment; (iii) at least one binder prepaint comprising at least one latex polymeric binder; and (iv) at least one prepaint comprising an aggregate; and
(b) dispensing a predetermined amount of each of the prepaints into containers or applicator(s) to form the paint line.
Further provided is a method of forming a range of paints. The range comprises at least two paint lines useful as a non-cementitious, aggregate finishing coatings. The method comprises the steps of:
(a) providing a set of different, but mutually compatible, fluid non-cementitious prepaints sufficient to formulate at least two paint lines, which set comprises: (i) at least one opacifying prepaint comprising at least one opacifying pigment; (ii) at least one extender prepaint comprising at least one extender pigment; (iii) at least one binder prepaint comprising at least one latex polymeric binder; (iv) at least one prepaint comprising aggregate; and (v) at least one additional different fluid prepaint selected from the group consisting of prepaints (i), (ii), (iii), and (iv); and
(b) dispensing a predetermined amount of each of the prepaints into containers or applicator(s) to form the paint lines.
In another embodiment, a set of different, but mutually compatible, fluid prepaints sufficient to form at least one paint line useful for forming pigmented and clear coatings is provided. The set comprises: (i) at least one opacifying prepaint comprising at least one opacifying pigment; and (ii) at least two binder prepaints, each of which comprises at least one latex polymeric binder;
In another embodiment, a set of prepaints sufficient to form at least one paint line useful in graphics art applications is provided. The set comprises: (i) at least one binder prepaint comprising at least one latex polymeric binder having a Tg of about xe2x88x9250xc2x0 C. to about 10xc2x0 C.; (ii) at least one binder prepaint comprising at least one latex polymeric binder having a Tg of about 50 to about 140xc2x0 C.; and (iii) optionally at least one binder prepaint comprising at least one latex polymeric binder having a Tg of about 0xc2x0 C. to about 65xc2x0 C. The graphic art prepaints may further comprise additional fluid mutually compatible prepaints selected from the group consisting of: (i) a prepaint comprising at least one alkali soluble resin; (ii) a prepaint comprising at least one gloss additive; (iii) a prepaint comprising at least one wax; and (iv) a plurality of prepaints comprising at least one pigment dispersion.
If one paint line is desired, i.e., if one key property is varied (for example, sheen level, tint base, use type, or quality type), then the complete paint line can be made from one each of the opacifying prepaint (i), the extender prepaint (ii), and the binder prepaint (iii).
If a range of paints including two paint lines is desired, i.e., if two key properties are varied (for example, two selected from sheen level, tint base, use type, and quality type) then the range of paints may be made from at least one each of the opacifying, extender, and binder prepaints (i), (ii) and (iii) and at least one additional different prepaint selected from the opacifying, extender, and binder prepaints (i), (ii), and (iii), depending on which key properties are to be varied.
If a range of paints including three paint lines is desired, i.e., if three key properties are varied (for example, three selected from sheen level, tint base, use type, and quality type) then the range of paints can be made from at least one each of the opacifying, extender, and binder prepaints (i), (ii) and (iii) and at least two additional prepaints different opacifying, extender, or binder prepaints, depending on which key properties are to be varied.
If a range of paints including four paint lines is desired, i. e., if four key properties are varied (for example, sheen level, tint base, use type, and quality type) then the complete range of paints can be made from at least one each of the opacifying, extender, and binder prepaints (i), (ii), and (iii) different and at least three additional different prepaints, opacifying, extender, and binder, depending on which key properties are to be varied.
This technique may be continued to vary as many additional key properties as desired.
By xe2x80x9cadditional opacifying, extender, and binder prepaintsxe2x80x9d is meant a prepaint different from the opacifying, extender, and binder prepaints (i), (ii), and (iii), respectively, but otherwise meeting the limitations associated with prepaints.
As discussed above, xe2x80x9cpaint linexe2x80x9d includes two or more different paints whose dried films differ materially from each other in at least one observable property. The paints are different from each other and must meet at least one of the following criteria:
(1) the pigment volume concentration (PVC) of the paints which are most different must differ by at least 2%; or
(2) the volume solids (VS) of the paints which are most different must differ by at least 2%.
The pigment volume concentration (PVC) is a measure of how xe2x80x9cbinder-richxe2x80x9d a formulation is. It is calculated herein using the following formula:       PVC    ⁢          xe2x80x83        ⁢          (      %      )        =                              volume          ⁢                      xe2x80x83                    ⁢          of          ⁢                      xe2x80x83                    ⁢                      pigment            ⁡                          (              s              )                                      +                  volume          ⁢                      xe2x80x83                    ⁢                      extender            ⁡                          (              s              )                                                                                                      volume                ⁢                                  xe2x80x83                                ⁢                of                ⁢                                  xe2x80x83                                ⁢                                  pigment                  ⁡                                      (                    s                    )                                                              +                              volume                ⁢                                  xe2x80x83                                ⁢                                  extender                  ⁡                                      (                    s                    )                                                              +                                                                          volume              ⁢                              xe2x80x83                            ⁢                              binder                ⁡                                  (                  s                  )                                                                          xc3x97    100  
The volume solids (VS) is the dry volume of pigment(s) plus the dry volume of extender(s) plus the dry volume of binder(s). It is calculated herein by the following formula:       VS    ⁢          xe2x80x83        ⁢          (      %      )        =                                                                        dry                ⁢                                  xe2x80x83                                ⁢                volume                ⁢                                  xe2x80x83                                ⁢                of                ⁢                                  xe2x80x83                                ⁢                                  pigment                  ⁡                                      (                    s                    )                                                              +                              dry                ⁢                                  xe2x80x83                                ⁢                volume                ⁢                                  xe2x80x83                                ⁢                of                ⁢                                  xe2x80x83                                ⁢                                  extender                  ⁡                                      (                    s                    )                                                              +                                                                          dry              ⁢                              xe2x80x83                            ⁢              volume              ⁢                              xe2x80x83                            ⁢              of              ⁢                              xe2x80x83                            ⁢                              binder                ⁡                                  (                  s                  )                                                                                total        ⁢                  xe2x80x83                ⁢        volume        ⁢                  xe2x80x83                ⁢        of        ⁢                  xe2x80x83                ⁢        formulation              xc3x97    100.  
If additives are present, their volume is not included in determining the total dry volume. In each of the above embodiments the prepaints are selected so that they cover a wide formulation space so that the desired final paint properties lie within the blend space defined by the prepaints at the extremes. In many cases the prepaints themselves will not be practical paints. But, by pushing the prepaints to these extremes one can maximize the blend space available for the set. When the prepaints, additives and colorants are all fully compatible, they can be blended at desired ratios to achieve the desired paint line(s) and range of paints without inducing colloidal instability. It is possible to make a specific paint in the paint line without utilizing each of the prepaints available in the set of prepaints. For example, a deep tone paint does not require the use of an opacifying pigment prepaint.
This technique is similar to the design principles used in statistical experimental design and analysis of mixture component designs; however, instead of designing a mixture space to explore the response surface within it, one is designing the boundaries of the mixture space to maximize the flexibility of the paint system. The key to success is to have mutual compatibility of the individual prepaint ingredients and prepaints across the mixture space.
Paint properties can be predicted in a number of ways. One approach is to develop response surface models of the blend space using standard Mixture Component experimental design statistical tools. These simple statistical models can then be used by a linear optimization program, by a massive grid search or by a graphical analysis tool. Another approach is to simply use empirical methods to determine which blends are needed for specific paint lines, then incorporate those simple empirical recipes in the paint making machine software.
An extension of the techniques is to have the paint machine automatically pretest certain key properties (e.g., viscosity, forced dry gloss or color) and make minor adjustments during the formulating of a paint from the prepaints. Having feedback loops in the paint machine can provide more precise matching of color, gloss, and viscosity targets.
Compatible paint ingredients can be combined in the various prepaints and the paints formed from the prepaints provide the properties characteristic of the amount of ingredient used.
It is preferred that the all fluid prepaints employed in the methods herein have the same or similar viscosities to aid in mixing.
The water-resistance, including blister resistance, wet adhesion, and scrub resistance of the paints prepared from the prepaint sets is expected to be improved because of the use of lower amounts of stabilizing materials such as surfactants which may be used relative to conventional formulating techniques. Further a line of pains or a range of paints prepared using the prepaints may react more predictably to added colorants, making color matching easier and facilitating the use of software for color matching. In addition, viscosity fluctuation in the final paint formulation is expected to be reduced because of the prior equilibration of ingredients in the prepaints.
The prepaints are formulated to maximize the flexibility of paint manufacturing. Rather than purchasing individual paint ingredients, paint manufacturers and even buyers at point-of-sale and point-of-use (paint stores, paint departments, and contractors), can purchase the set of prepaints to prepare a desired range of paints. These sets of prepaints will contain at least one each of prepaints x, y and z and possibly additional prepaints depending upon the formulating flexibility desired. Optionally, the above prepaints are mixed with an additional prepaint which includes at least one colorant, such as a colored pigment or dye.
The prepaint sets and formulating methods herein are not limited to the preparation of only latex paints. They may also be used to prepare any water-borne coating or related building products which require mixing ingredients, including, but not limited to, graphic arts, sealants, caulks, mastics, adhesives, architectural coatings (homeowner-applied and contractor-applied wall coatings, elastomeric wall and roof coatings and aggregate finish layers) and industrial coatings (such as those classified as original equipment manufacturing, maintenance, wood, metal, general industrial finishes, and other factory-applied coatings as well as a minor portion of non-architectural type coatings applied by do-it-yourselfers).
In the industrial coatings area, the methods herein may be applied to a broad range of coatings for automotive, marine, aircraft, other land transportation, appliances, metal furniture, machinery and equipment, coil, metal containers, magnetic wire, concrete roof tile, insulating varnish, electronic, pipe, packaging, overprint, release, flatboard, wood furniture, plastic substrates, magnetic media, general metal, industrial maintenance, automotive refinish, traffic paint, fire retardant, aerosol, chemical agent resistant coating, roof, tank, deck, concrete, masonry water repellent, nail polish, art and hobby uses. For example, the method herein may be applied to produce a range of metal coatings, including flat, gloss, direct-to-metal, primer, mid-coat and solvent resistant coatings, using an appropriate set of prepaints.
In one embodiment of the opacifying prepaint, the prepaint is a fluid titanium dioxide prepaint which includes (i) at least one opacifying pigment, (ii) at least one dispersant, (iii) at least one thickener, and water. The dispersant(s) and the thickener(s) are compatible with the pigment(s) and with other optional paint ingredients. The prepaint has a volume solids content of about 30% to about 70%, preferably about 35% to about 50% and a Stormer viscosity of about 50 to about 250 KU, preferably about 60 to about 150 KU.
In an alternate embodiment, the opacifying prepaint is a fluid titanium dioxide prepaint useful for formulating a one pack, pigmented latex paint containing other paint ingredients. The prepaint includes (i) at least one opacifying pigment, (ii) at least one dispersant, (iii) at least one thickener, (iv) at least one film-forming or nonfilm-forming polymeric binder, and (v) water. The dispersant(s), the thickener(s), and the polymer(s) are compatible with the pigment(s) and with other optional paint ingredients. The prepaint has a volume solids content of about 30% to about 70%, preferably about 35% to about 50%, a PVC of about 35% to about 100%, preferably about 50% to about 100%, and a Stormer viscosity of about 50 to about 250 KU, preferably about 60 to about 150 KU. Preferably, the prepaint is stable to sedimentation, by which is meant herein that the pigment does not settle out after 10 days at 25xc2x0 C. Optionally, the polymeric binder is adsorbed onto the opacifying pigment.
In one embodiment of the extender prepaint, it is a fluid pigment extender prepaint which includes (i) at least one mineral extender, (ii) at least one thickener, (iii) an optional polymeric binder, and (iv) water. The pigment extender prepaint has a volume solids content of about 30% to about 70%, preferably about 35% to about 65%, a PVC of about 35% to about 100%, preferably about 40% to about 100%, and a Stormer viscosity of about 50 to about 250 KU, preferably about 60 to about 150 KU. The prepaint ingredients are compatible with each other and with the ingredients of the other prepaints desired to be used therewith.
In one embodiment of the binder prepaint, it is a fluid latex polymeric binder prepaint which includes a water-borne latex polymeric binder having a Tg of about xe2x88x9240xc2x0 C. to about 70xc2x0 C., preferably about xe2x88x9210xc2x0 C. to about 60xc2x0 C., and water. The binder prepaint has a volume solids content of about 25% to about 70%, preferably about 30% to about 65%, and a Brookfield viscosity of less than about 100,000 centipoise, preferably about 100 to about 50,000 centipoise, at a shear rate of 1.25 reciprocal seconds. The prepaint ingredients are compatible with each other and with the ingredients of the other prepaints desired to be used therewith.
In the embodiments of prepaints the opacifying, extender, and binder prepaints (i), (ii), and (iii), it is optional to include minor amounts, i.e., less than about 20% by weight, based on the total weight of the prepaint, of conventional paint additives including an acid, a base, a defoamer, a coalescent, a cosolvent, a mildewcide, a biocide, an antifreeze agent, a flash rust inhibitor, and the like. These additives must be compatible with the other paint ingredients in the prepaints and the paints employed in the methods herein.
Suitable opacifying pigments include white pigments which impart white scattering power to the paint across all visible wavelengths without a high degree of absorption. Pigment extenders are inorganic solids or opaque polymers which do not impart the primary color or hiding power to the paint although they may have secondary influences on those properties. The tint bases used for deep tone paints typically contain no or only very low levels of opacifying pigments.
Suitable opacifying pigments include titanium dioxide (TiO2) or a combination of titanium dioxide and auxiliary hiding pigments such as voided latex polymer particles, zinc oxide, lead oxide, a synthetic polymer pigment and mixtures thereof. Rutile and anatase grades of titanium dioxide are suitable for use herein. Rutile titanium dioxide is preferred. The surface of these titanium dioxides may be treated with various organic surface treatments and/or inorganic surface treatments, e.g., treatment with the oxides of silica, alumina, and zirconia. Fumed titanium oxide is also useful herein.
Suitable voided latex particles have a diameter of about 100 nm to about 2,500 nm and a void fraction of about 10% to about 75%. Preferably, the voided latex particles useful in the method of the invention have a particle size of about 500 nm to about 1,100 nm. OK particles have at least one void, but may have multiple voids, non-spherical voids, interconnected voids, voids having channels connected to the outside of the particles, and other structures described as vesiculated and spongelike. Preferably, the (Tg) have a single void. The particles have a glass transition temperature, as measured by differential scanning calorimetry at a rate of 20xc2x0 C./min, of at least about 20xc2x0 C., preferably at least about 50xc2x0 C. The higher the Tg, the harder is the particle, making it less likely it is to collapse. If the voided latex particles collapse, they are unable to contribute to hiding. Voided latex particles they may be prepared by conventional polymerization processes known in the art, such as those disclosed in U.S. Pat. No. 3,784,391, U.S. Pat. No. 4,798,691, U.S. Pat. No. 4,908,271, U.S. Pat. No. 4,972,000, U.S. Pat. No. 5,041,464, U.S. Pat. No. 5,157,084, U.S. Pat. No. 5,216,044 and U.S. Pat. No. 6,020,435, as well as Japanese Patent Applications 60/223,873, 61/62510, 61/66710, 61/86941, 62/127336, 62/156387, 01/185311, and 02/140272. Preferably, the voided latex particles are prepared according to U.S. Pat. No. 4,427,836, U.S. Pat. No. 4,469,825, U.S. Pat. No. 4,594,363, U.S. Pat. No. 4,880,842, U.S. Pat. No. 5,494,971 and U.S. Pat. No. 020,435.
Extender pigments useful herein include exterior and interior extender pigments optimized for the intended end use. Exterior extender pigments are not soluble in water and have a low absorption number. They are optimized for exterior durability in the particular market where the paint will be sold, and they do not detract from the desired non-cracking, non-chalking, and non-dirt-retaining properties of the dried paint. They also provide volume at a low cost. Interior extender pigments are optimized for hiding, gloss, and low cost. Suitable extender pigments include barium sulfate (1-15 microns), Blanc Fixe (0.5-5 microns), calcium carbonate (0.05-35 microns), silica (0.001-14 microns), magnesium silicate (0.5-15 microns), aluminum silicate (0.2-5 microns), nepheline syenite, mica, bentonite, magnesium alumino-silicate, fumed allumina, colloidal attapulgite, synthetic amorphous sodium alumino-silicate, sodium potassium alumino-silicate, and the like.
Latex polymeric binders are polymers or prepolymers which form the primary paint film. They bind the pigment and/or extenders, provide the required paint flow, and determine the gloss and hardness of the final paint film. The binders selected for the prepaints will depend upon the final use of the formulated paints. Binders suitable for exterior paints are generally suitable for interior paints, but binders suitable for interior paints may not be suitable for exterior paints.
Suitable latex polymeric binders include, but are not limited to, homopolymers, copolymers or terpolymers such as, for example, acrylic and/or methacrylic polymers or copolymers, polyvinyl acetate, styrene-acrylic copolymers, styrene-butadiene, vinyl acetate-acrylic copolymers, ethylene-vinyl acetate copolymers, vinyl acetate-vinyl versatate copolymers, vinyl acetate-vinyl maleate copolymers, vinyl acetate-vinyl chloride-acrylic terpolymers, ethylene-vinyl acetate-acrylic terpolymers, and urethane polymers. The polymers may contain up to 10% by weight of functional monomers, (for example, but not limited to, carboxylic acid, phosphate, sulfate, sulfonate and amide) groups, other monomers, and mixtures thereof. Latex polymeric binders optionally incorporated in prepaints x, y, xxe2x80x2, yxe2x80x2, or other prepaints may be the same as or different from the latex polymeric binder of prepaint z.
It is conceivable that for industrial coatings the prepaints will employ a wide range of thermoplastic and thermosetting polymeric binders, that may be one-pot, two-pot or energy-curable, in the prepaints and methods of the inventions, including but not limited to: asphalt, paraffin wax, coal tar, alkyds, vinyl acetate, vinyl acetate/acrylic, styrene-butadiene, saturated polyester, unsaturated polyester, polyurethane, acrylic lacquer, acrylic enamel, acrylic latex, acrylic thermosetting, acrylic electrodeposition and autodeposition, styrene acrylic, vinyl toluene acrylic, radiation-curable acrylic, melamine, urea, epoxy (diglycidyl ether of bisphenol A, bisphenol F, cycloaliphatic, monofunctional epoxies and the like), vinyl acetate copolymer N-methylolacrylamide, vinyl acetate-ethylene, vinyl acetate terpolymer, vinyl acetate-vinyl versatate, polyvinyl chloride, polyvinylidene chloride, ethylene-acrylic acid, ethylene-methacrylic acid, ionomer, ethylene-methyl acrylate, cellulosics, nitrocellulose, cellulose acetate butyrate, shellac, phenolic, ethyl silicate, polyacetals, styrene-allyl alcohol, chlorinated rubber, polyvinyl alcohol, butyl rubber, styrenexe2x80x94ethylene butylenexe2x80x94styrene block copolymer rubber, urethane acrylate, polyamideimide, polyesterimide, silicones, silanes, shellac, polyamides, polytetrafluoroethylene, polydiallyldimethylammonium chloride, polyphenylene sulfide, aromatic polyester, polyimide, siliconeimide, fluoropolymers, parylene, aramid, stelarate polymers, oleoresinous, and chlorinated polyolefin and bis-cyclobenzobutene, The polymeric binders are preferably water-borne latexes, but may also be solvent-borne, water reducible, redispersible latexes, and combinations thereof.
The polymeric binders may be one-pack or two-pack. If the polymeric binders are two-pack, the polymeric binders may be used by:
(1) separating one component of the two-pack system as a separate prepaint;
(2) separating one component of the two-pack system and including it in either the opacifying prepaint or the extender prepaint;
(3) adding one component of the two-pack system separately from any of the prepaints; and
(4) combinations thereof.
Thickener is a general term used to describe any material added to a paint to modify its rheological profile. Preferred thickeners are associative thickeners. Suitable thickeners for use herein include polyvinyl alcohol (PVA), hydrophobically-modified, alkali soluble emulsions known in the art as HASE emulsions, alkali-soluble or alkali, swellable emulsions known in the art as ASE emulsions, hydrophobically, modified ethylene oxide-urethane polymers known in the art as HEUR thickeners, and cellulosic thickeners such as hydroxymethyl cellulose (HMC), hydroxyethyl cellulose (HEC), hydrophobically-modified hydroxy ethyl cellulose (HMHEC), sodium carboxymethyl cellulose (SCMC), sodium carboxymethyl 2-hydroxyethyl cellulose, 2-hydroxypropyl methyl cellulose, 2-hydroxyethyl methyl cellulose, 2-hydroxybutyl methyl cellulose, 2-hydroxyethyl ethyl cellulose, 2-hydoxypropyl cellulose, and the like. Also useful as thickeners are fumed silica, attapulgite clay and other types of clay, titanate chelating agents, and the like.
Suitable dispersants for use herein include non-ionic, anionic and cationic dispersants such as 2-amino 2-methyl 1-propanol (AMP), dimethyl amino ethanol (DMAE), potassium tripolyphosphate (KTPP), trisodium polyphosphate (TSPP), citric acid and other carboxylic acids, and the like. Also suitable for use as dispersants are Anionic polymers such as homopolymers and copolymers based on polycarboxylic acids, including those that have been hydrophobically- or hydrophilically-modified, e.g., polyacrylic acid or polymethacrylic acid or maleic anhydride with various monomers such as styrene, acrylate or methacrylate esters, diisobutylene, and other hydrophilic or hydrophobic comonomers as well as the salts of the aforementioned dispersants, and mixtures thereof.
Suitable defoamers include silicone-based and mineral oil-based defoamers, and the like.
Coalescents are not necessary if solvent-free latex polymer binders are used in the binder prepaints. Solvent-free binders typically have a low Tg and low minimum film-forming temperature so that they are film-forming at ambient temperatures, such as 20xc2x0 C. If a coalescent is required, preferably it is incorporated in the binder prepaint and any other prepaints containing latex polymer binders.
Suitable coalescents, plasticizers, and other optional solvents include ethylene glycol, propylene glycol, hexylene glycol, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (TEXANOL(trademark)), glycol ethers, mineral spirits, methyl carbitol, butyl carbitol, phthalates, adipates, and the like.
Suitable mildewcides and biocides include zinc oxide, isothiazolones, triazoles, and the like.
Suitable surfactants include cationic, anionic, and non-ionic surfactants.
Suitable aggregates include small (typically 40 mesh and higher), intermediate (typically 20-40 mesh) and large (typically 20 mesh and lower) aggregates, such as sand, large particle size carbonates (limestone), ceramics, glass, fibers, coal, granite, talc, multicolored quartz, crushed sea shells, recycled products such as asphalt-containing materials, fiberglass, vermiculite, perlite, XO aggregate and the like.
Suitable flash rust inhibitors include aminoethylethanol amine, ammonium benzoate, sodium nitrite, ammonia benzoate, ammonium and amine salts of dicarboxylic acids and diphenols, such as glutaric acid, malonic acid, suberic acid, sebacic acid, adipic acid, succinic acid, phthalic acid, isophthalic acid, terephthalic acid, thidiphenol and sulfonyldiphenol and their ammonium and amine-complexed zinc salts, C-12 to C-14-tert-alkylamines, compounds with (2-benzothiazolythio)-butanedioic acid; (2-benzothiazolyltio) butanedioic acid, 4-oxo-4-p-tolylbutryic acid adduct with 4-ethylmorpholine, zirconium complex with 4-methyl-xcex4-oxo-benzene-butanoic acid and the like.
Suitable crosslinkers include multivalent metal ions, such as zinc, magnesium, zirconium, calcium and like ions.
Reactive pigments are materials that are added to coating formulations to confer corrosion resistance by sacrificially corroding on behalf the substrate. Suitable reactive pigments include calcium zinc phosphomolydate, zinc phosphate, aluminum triphosphate, strontium zinc phosphosilicate, molybdate-modified zinc phosphate and the like.
Suitable waxes include carnauba, paraffin, polyethylene, micronized ethylene-acrylic acid, polytetrafluoroethylene (PTFE), and the like.
Alkali-soluble resins are polymers that contain sufficient acid functionality and low enough molecular weights to dissolve in an aqueous media when neutralized with base. They exhibit Newtonian rheology, and act as a dispersant (i.e, reduce the surface tension of the aqueous medium). Suitable alkali- soluble resins include esters of acrylic acid and methacrylic acid copolymerized with carboxylic acid monomers (such copolymers, for example, are available from the Rohm and Haas Company and sold under the trade names Acrysol(trademark) I-62 and Acrysol(trademark) I-2074), copolymers of styrene and acrylic acid with optional alpha-methyl styrene (such polymers, for example, are available from the Rohm and Haas Company and sold under the trade name Morez(trademark) 101), styrene/maleic anhydride copolymers, and the like.
In another preferred embodiment, the prepaints and methods of the present invention may be used to make elastomeric coatings suitable for either wall or roof applications. These prepaints may be mixed in various ratios to obtain elastomeric coatings of different quality, flexibility, mildew protection, and substrate adhesion suitable for either application on wall or roofs.
The main feature that distinguishes elastomeric coatings from typical architectural coatings is the use of binders with low temperature ( less than 0xc2x0 C.) flexibility and the thickness at which the coating is applied (typically a dry coating thickness of about 6 to about 20 mil for wall applications and about 15 to about 40 mil for roof applications). Low temperature flexibility is particularly desirable for elastomeric coatings when they are being used over walls that may develop cracks, such as masonry walls, or roofing substrates that have a high degree of dimensional variance with climate. In addition to coating flexibility, it is desirable to have an elastomeric coating line with different degrees of low temperature flexibility, different qualities, ability to adhere to different substrates, and variations in appearance.
For a climate that experiences freezing temperatures through the winter, the following characteristics can be used to describe the different quality levels:
Quality Level
For a climate that has only a few days of freezing temperatures through the winter, the following characteristics can be used to describe the different quality levels:
Quality Level
The quality of the elastomeric coating may be varied further depending on whether or not zinc oxide (ZnO) is present in the formulation. Zinc oxide changes the mechanical properties of the coating.
Finally, the elastomeric coating may be further varied through the addition of colorants. Typically, these colorants are dry ground and made in the coating grind portion.
For elastomeric coatings, one may define the following properties that may be varied in the coating manufacture to make different elastomeric coatings: coating flexibility, coating quality (durability), substrate adhesion and appearance
To differentiate based on the flexibility of the elastomeric coating, one may adjust the Tg of the binder, the PVC of the coating, and the presence and level of zinc oxide. To differentiate based on the durability of the elastomeric coating, one may adjust the level of titanumdioxide (TiO2). To differentiate based on the adhesion of the elastomeric coating to a substrate, one may formulate to coat a wall or a roof by varying the binder composition and level. To differentiate based on the appearance of the elastomeric coating, one may adjust the level and type of colorant. To obtain these different properties one may prepare a set of prepaints as set forth in Examples 36-41 below, and mix them in appropriate quantities to make elastomeric coatings that vary the properties described above.
In another preferred embodiment, the prepaints and methods herein may be used to make non-cementitious, aggregate finish coatings suitable for application on a wall directly or as a topcoat in exterior insulation and finishing systems (EIFS). These prepaints or preformulated components may be mixed in various ratios to obtain coatings of different flexibility, quality (durability), color, and texture.
The following formulation properties provide an example of how one may influence the durability of its non-cementitious, aggregate finish coatings used specifically for EIFS. Other types of aggregate finishes may have different ranges of PVC that correspond to different qualities. Therefore, the description below is only meant to be an example for aggregate finish coatings used in EIFS, and is not meant to define the PVC levels used in other non-cementitious, aggregate finish coatings.
Quality
In addition, one may define the following formulation properties that affect color strength. Other types of aggregate finishes may have different TiO2 levels that correspond to different color strengths. Therefore, the description below is only meant to be an example for aggregate finish coatings used in EIFS, and is not meant to define TiO2 levels used in other aggregate finishes.
Finally, one may also define the following formulation properties that affect coating texture.
Further variations in aggregate finish performance can be achieved by varying binder flexibility or Tg.
As a specific embodiment of this invention relating to non-cementitious, aggregate finish coatings, one may vary the following properties in the coating manufacture to make different coatings: PVC level, TiO2 level, Aggregate ratio and Binder Tg.
To differentiate based on the flexibility of the non-cementitious, aggregate finish coatings, one may adjust the Tg of the binder. To differentiate based on the durability of the non-cementitious, aggregate finish coatings, one may adjust the PVC of the coating. To differentiate based on the color the non-cementitious, aggregate finish coatings, one may adjust the level of TiO2 and the type and level of colorant. To differentiate based on the texture of the non-cementitious, aggregate finish coatings, one may adjust the size and level of the large aggregate and the ratio of the large aggregate to small aggregate. To obtain these different properties one may prepare a set of prepaints as set forth in Examples 54-58 below, and mix them in appropriate quantities to make non-cementitious, aggregate finish coatings that vary the properties described above.
In another preferred embodiment, the prepaints may be used in the methods of the invention to form a range of coatings useful where some of the coatings contain opacifying and/or extender pigments and where some of the coatings do not contain opacifying pigments (xe2x80x9cclearsxe2x80x9d). These coatings may be applied over a variety of substrates, including metal, wood, and cementitious substrates, such as concrete roof tiles.
In another preferred embodiment, the prepaints may be used in the methods herein to form a range of graphic arts paint lines useful for a number of applications including, but not limited to, inks for giftwrap paper, corrugated substrate, newsprint, paperboard, labels, freezer bags, storage bags, metal films, foils; as well as overprint coatings applied for general purposes such as water-resistance, rub-resistance and high slip.
All ranges disclosed herein are inclusive and the minimums and maximums of the nested ranges are combinable.
Test Procedures
The Stormer viscosity of the prepaints is measured using ASTM method D562. The Brookfield viscosity of the binder prepaints and final paints is measured using spindle #4 of a Brookfield viscometer at 6 rpm. The ICI viscosity of the prepaints and paints is measured using ASTM method D3205-77. Glass transition temperature (xe2x80x9cTgxe2x80x9d) may be measured via differential scanning calorimetry at a rate of 20xc2x0 C./minute.